introduction to shim6
TRANSCRIPT
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机密
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sando09/10/2005
Site-Multihoming
over IPv6
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Outline
• Routing difference between IPv6 and IPv4• Goals for Site-Multihoming• shim6: A proposed solution• Phylogeny of shim6 • Deficiencies and Questions of shim6• Some ideas of sando• Resource and References
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Routing difference between IPv6 and IPv4
• In a site’s eyes:– more IP addresses– more Internet service providers– more routing paths– better performance
• In a ISP’s eyes:– more access sites– more routing exits (more uplink ISPs)– more routing policies– better management
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Routing difference between IPv6 and IPv4
Multihoming!!!
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Goals for Site-Multihoming
• Compatible IPv4 Multihoming– Redundancy, Load sharing, Performance– Policy, Simplicity– Transport-Layer Survivability, Impact on DNS– Packet Filtering
• Additional Requirements– Scalability– Impact on Routers, Hosts (single-homed still goes)– Interaction between Hosts and Routing System– Operations and Management– Cooperation between Transit Providers– Multiple Solutions
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shim6
• Level 3 shim for IPv6– modification of the Internet Protocol stack element
within the protocol stack of the endpoint
AH ESP Frag/reassIP EndpointSub-layer Dest opts
Shim6insert
IP
Multi6Sub-layer
IP RoutingSub-layer
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Sender A
shim6
• The shim layer provides a set of associations between endpoint identity pairs and locator sets
shim6
Network PathULP
IP
Src ULID(A)Dst ULID(B)
Src L(A)Dst L(B)
Receiver B
shim6
ULP
IP
Src ULID(A)Dst ULID(B)
Src L(A)Dst L(B)
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shim6
• ULID – Upper-Layer Identifier– Locator: topological name of a set of interfaces– Use one of the locators?– shim6 select locator pairs for routing– Locators can be reversed by ULID & DNS – ULA and other assumptions…
• Walkthrough
Applicationget locators
throughFQDN
use one to create
connection
sending&
receivingpackets
try toestablishshim6
with remote
change todifferentlocatorpeers
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Phylogeny of shim6
• Multi6 Working Group– Dec 04 Identify proposals for further development, recharter
• Shim6 Working Group– Oct 05 WG last-call on architectural document – Oct 05 WG last-call on applicability statement document – Feb 06 WG last-call on protocol document – Feb 06 WG last-call on cryptographic locators, if required – Feb 06 Submit completed architectural document to IESG – Feb 06 Submit applicability statement document to IESG – Apr 06 WG last-call on multihoming triggers description – Apr 06 Submit document on cryptographic locators to the IESG, if required – Apr 06 Submit protocol document to the IESG – Jun 06 Submit draft on multihoming triggers description to the IESG
• Recent Activity– Oct 08 & 09, Interim meeting by Geoff Huston and Kurt Lindqvist – Nov 06, IETF regular meeting
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Deficiencies and Questions of shim6
• Signaling interface between shim6 and upper layers pf
• Incoming locator pair mapped to an equivalent ULID pair
• Unreachable ULIDs & reachable locator search• Ambiguity of demultiplexing • Treatment of trigger conditions for locator change • Interaction between locator pair selection, local
forwarding decision, site exit routers and packet ingress filters on the immediately adjacent upstream provider routers
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Deficiencies and Questions of shim6
Goals of shim6
Applicability
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Some Ideas
SecureAttach
VIPRouting?
ISPManage
AS Multihoming
shim6
HBAGenuine
Addr
Perform
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Resource and References
• RFC3582, ‘Goals for IPv6 Site-Multihoming Architectures’
• draft-ietf-shim6-arch-00, ‘Architectural Commentary on Site Multi-homing using a Level 3 Shim’
• multi6– https://ops.ietf.org/lists/multi6
• shim6– [email protected]
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Need further discussion